The heart of a computer is a magnetic disk drive which typically includes a rotating magnetic disk, a slider that has read and write heads, a suspension arm above the rotating disk and an actuator arm that swings the suspension arm to place the read and/or write heads over selected circular tracks on the rotating disk. The suspension arm biases the slider into contact with the surface of the disk when the disk is not rotating but, when the disk rotates, air is swirled by the rotating disk adjacent an air bearing surface (ABS) of the slider causing the slider to ride on an air bearing a slight distance from the surface of the rotating disk. When the slider rides on the air bearing the write and read heads are employed for writing magnetic impressions to and reading magnetic signal fields from the rotating disk. The read and write beads are connected to processing circuitry that operates according to a computer program to implement the writing and reading functions.
Data tracks are typically written to the disk in concentric tracks positioned at various radial locations. For reliability purposes, adjacent track erasure tests are often performed to determine how many writes to a given data track may be performed before an erasure of the adjacent track or tracks is detected. Typically, the minimum number of writes is in the tens or hundreds of thousands of writes. Accordingly, during adjacent track erasure testing, tens or hundreds of thousands of write and read cycles are performed. This is very time consuming, and thus costly, and usually must be done after a track pitch is determined.